|Small joint arthoplasty has been an
ongoing problem of hand surgery. The delicate and anatomically precise
joints of the fingers function within a very narrow tolerance of friction
and mechanical balance of bone and soft tissue forces. Historically, rigid
(metal and plastic) implants have failed because the mechanical mismatch
at the bone-implant interface has resulted in implant displacement due
to reactive bone remodelling. Flexible (silicone rubber) implants have
failed because of implant breakage, erosive reaction to implant wear debris,
and inability of flexible implants to provide rotational and lateral stability.
Pyrolytic carbon implant arthroplasty of the finger joints appears to be an improvement on previous strategies, as it mimics the normal joint mechanics, lack of wear debris and a close match to the mechanical characteristics of the finger bones.
|Click on each image for a larger picture|
|Pyrolytic carbon implants for proximal interphalangeal joints (above) and metacarpophalangeal joints (below). Another proximal interphalangeal joint post traumatic reconstruction is shown here and an example of metacarpophalangeal joint implants is posted here.|
|These are before and after radiographs
of middle and ring proximal interphalangeal joints in a young man after
a rotating blade injury resulting in dorsal bone and soft tissue loss.
Initially treated elsewhere with K wire fixation, ring finger skin graft
and abdominal flap reconstruction of the middle finger, he presented with
instability, stiffness, pain and lateral angulation. Surgery was technically
difficult because normal landmarks were distorted or missig. Despite complex
bone and soft tissue loss, stability was rendered in part by the
restoration of concentric joint surfaces.
|Correction of alignment.|
|Correction of lateral deviation.|
interphalangeal implant arthroplasty
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